Cardlock clamp

ABSTRACT

A cardlock clamp is described that is used to secure an electronics module in a channel of a card cage. The cardlock clamp is configured to convert an input compression force into clamping forces in at least two radial directions perpendicular to the input compression force. The described cardlock clamp also provides self-alignment and self-center functions for the electronics module inserted into the channel. Further, variations of the cardlock clamp are described that provide more effective heat transfer from the electronics module to the card cage.

FIELD

This disclosure relates to a clamp, and more particularly to a cardlockclamp to secure an electronics module.

BACKGROUND

In certain applications, a circuit card is secured in a channel in achassis of a card cage by a clamping device in the form of a wedgelockdevice. In addition to securing the circuit card, the clamping device isoften configured to provide some thermal interface between the circuitcard and the card cage to remove heat from the circuit card to the cardcage.

SUMMARY

A cardlock clamp is described that is used to secure an electronicsmodule such as a circuit card in a channel in a chassis of a card cage.The described cardlock clamp is configured to convert an inputcompression force into clamping forces in at least two radial directionsperpendicular to the compression force. The clamping forces areuniformly distributed along the longitudinal axis of the cardlock clampand the ratio between the clamping forces in the at least two radialdirections is adjustable. The described cardlock clamp also providesself-centering and self-alignment functions with respect to the circuitcard and the card cage. Further, the described cardlock clamp isconfigured to provide a more effective means of transferring heat fromthe circuit card to the card cage, for example via the surface of thecardlock clamp.

In contrast, conventional wedgelock devices function based on an inputtensile force to create a clamping force, and only clamp in onedirection. Further, conventional wedgelock devices transfer thermalenergy by means of conduction from the circuit cards through thewedgelock device body, which can be a slow and inefficient process andis highly dependent on the thermal flow path cross-section in contactwithin and contact pressure at the interface surfaces.

In one disclosed example, a cardlock clamp used to secure an electronicsmodule in a channel includes a member that is expandable in at least tworadial directions. The member includes an input compression forcemechanism. The input compression force mechanism is configured to applya compression force in a z-direction substantially perpendicular to theat least two radial directions. A plurality of force converting elementsare provided in the member and are engageable with the member. The forceconverting elements are engageable with the input compression forcemechanism and are configured to convert the compression force of theinput compression force mechanism into clamping forces that act on themember in the at least two radial directions in order to transfer theclamping forces to the member.

In another disclosed example, a cardlock clamp used to secure anelectronics module in a channel includes a first surface that in usecontacts the electronics module and a second surface that in usecontacts a heat sink and being connected to the first surface. The firstsurface and the second surface include a thermally conductive materialhaving at least one material selected from the group consisting ofdiamond, copper, aluminum, carbon nano-tubes, and their compounds. Whenthe cardlock clamp is installed in the channel, the first surfaceengages the electronics module, the second surface engages the heatsink, and heat is transferred from the electronics module to the heatsink.

In another disclosed example, a cardlock clamp used to secure anelectronics module in a channel includes a clamp body having a firstmoveable bracket configured as a heat pipe. The heat pipe has avaporization side configured to engage the electronics module when thecardlock clamp is installed in the channel, a condensing side spacedfrom the vaporization side and configured to engage a heat sink when thecardlock clamp is installed in the channel, and a two-phase heattransfer fluid within the heat pipe. The cardlock clamp further includesa mechanism for applying a clamping force to the first bracket.

In another disclosed example, a clamp mechanism includes an inputcompression force mechanism that is configured to input a compressionforce in a z-direction. A plurality of force converting elements engagewith the input compression force mechanism and are configured to convertan compression force input of the input compression force mechanism intoclamping forces in at least two radial directions. The at least tworadial directions are substantially perpendicular to the z-direction.

DRAWINGS

FIG. 1 is a side view of a circuit card mounted in a channel of a cardcage and secured by a cardlock clamp described herein.

FIG. 2( a) is a perspective view of an embodiment of a cardlock clampdescribed herein with two L-shaped brackets.

FIG. 2( b) is an exploded perspective view of the cardlock clamp of FIG.2( a) with one bracket lifted and showing double ended wedges that actas force converting elements.

FIG. 2( c) is another exploded perspective view of the cardlock clamp ofFIG. 2( a) with some of the double ended wedges out of the brackets.

FIG. 3( a) illustrates a perspective view of an exemplary double endedwedge.

FIG. 3( b) illustrates one embodiment of forming the double ended wedge.

FIG. 4( a) illustrates another embodiment of an exemplary double endedwedge engaged with two end pieces.

FIG. 4( b) illustrates an exploded perspective view of the double endedwedges of FIG. 4( a) engaged with each other and with the end pieces.

FIG. 5 illustrates an end view of the cardlock clamp of FIG. 2( a) in alocked position and showing the resulting clamping forces.

FIG. 6( a) illustrates a partial cross sectional view of anotherembodiment of a cardlock clamp having a horizontal wave spring and twovertical wave springs.

FIG. 6( b) is a perspective view of the wave springs inside the cardlockclamp of FIG. 6( a) with the horizontal wave spring flanked orthogonallyby the two vertical wave springs.

FIG. 7( a) is a side view of spring pins engaged with each other thatcan be used in another embodiment of a cardlock clamp.

FIG. 7( b) is a perspective view of a single spring pin having anexpandable sleeve section with a gap and a tang section.

FIG. 8 is a perspective view of another embodiment of a cardlock clampusing the spring pins.

FIG. 9 is an exploded perspective view of another embodiment of acardlock clamp using tubes.

FIG. 10( a) illustrates an end view of another embodiment of cardlockclamp with a diamond coating on the surface.

FIG. 10( b) is a cross sectional blow-up view of the diamond coating onthe surface of the cardlock clamp of FIG. 8( a).

FIG. 11 illustrate an end view of another embodiment of cardlock clampwith movable brackets configured as heat pipes.

DETAILED DESCRIPTION

A cardlock clamp is described that is used to secure a circuit card in achannel of a card cage. The described cardlock clamp converts an inputcompression force into clamping forces in at least two radial directionsperpendicular to the compression force. The described cardlock clampalso provides self-alignment and self-center functions with respect tothe circuit card and the card cage. Further, the described cardlockclamp can also provide a more effective means of transferring heat fromthe circuit card.

FIG. 1 illustrates an exemplary working environment for a cardlock clamp200 described herein to secure a circuit card 110 in a channel 120 in achassis of a card cage 100. The card cage 100 has at least one channel120 extending along a z-direction. Each of the channels 120 is definedby two side surfaces and a bottom surface. All the surfaces of onechannel can be a heat sink for the circuit card to be secured therein.The circuit card 110 has a flange 112 protruding from one end of thecircuit card 110 into the channel 120. When the circuit card 110 ismated in one of the channels 120 of the card cage 100, the cardlockclamp 200 is disposed between the flange 112 and one of the sidesurfaces of the channel 120 to clamp the circuit card 110 in the channel120.

The cardlock clamp 200 is configured to convert an input compressionforce applied in the z-direction into clamping forces in fourdirections, such as along the x-direction and the y-direction,simultaneously. The x-direction, the y-direction and the z-direction areperpendicular to each other. In the y-direction, the cardlock clamp 200is expandable to make positive contact with the flange 112 of thecircuit card 110 on one side and make positive contact with one of theside surfaces of the channel 120 on the other side. At the same time,the flange 112 of the circuit card 110 is pushed by the cardlock clamp200 to make positive contact with the other of the side surfaces of thechannel 120. In this manner, the circuit card 110 is secured by thecardlock clamp 200 in the channel 120 of the card cage 100. In thex-direction, the cardlock clamp 200 is also expandable to make positivecontact with the circuit card 110 on one side and make positive contactwith the bottom surface of the channel 120 on the other side so that thecardlock clamp 200 is self-aligned and self-centered with respect to thecircuit card 110 and the channel 120 of the card cage 100. Heat can betransferred from the circuit card 110 to the heat sink through thecardlock clamp 200.

In another exemplary working environment, a circuit card has two flanges(such as the flange 112) at two opposite ends of the circuit card. Theflanges protrude into two channels of a card cage (such as the card cage100) and secured by two cardlock clamps (such as the cardlock clamp 200)in a manner described above in FIG. 1. Each of the cardlock clamps isexpandable in at least two radial directions (such as the x-directionand the y-direction) so that the cardlock clamps push against oneanother through the circuit card and exert contact pressure on bottomsurfaces of both channels to secure the circuit card in the card cage.

FIGS. 2( a), 2(b), 2(c), 3(a), 3(b) and 4 illustrate a first embodimentof the cardlock clamp 200 used to secure a circuit card in a channel. Inthe illustrated embodiment, the cardlock clamp 200 has a member in theexemplary form of two elongated L-shaped brackets 202 and 204. TheL-shaped brackets 202 and 204 extend in the z-direction, are aligned ata first end and a second end, and when assembled define a cavity thatreceives a plurality of force converting elements. The force convertingelements, described further below, are engageable with one or more inputcompression force mechanisms and are configured to convert an inputcompression force into clamping forces that act on the L-shaped bracketsin order to transfer the clamping forces to the L-shaped brackets.

Each of the L-shaped brackets has two inner surfaces 206 a, 206 b andtwo outer surfaces 208 a, 208 b. The inner and outer surfaces aresubstantially perpendicular to the x-direction or the y-direction. TheL-shaped brackets 202 and 204 are movable relative to each other in thex-direction and in the y-direction. Although two L-shaped brackets aredescribed, any other number of brackets or any other shaped brackets canbe used. For example, four separate plates can be used as the bracketsto define the cavity.

The input compression force mechanisms of the cardlock clamp 200 includetwo screws 210 and 212 disposed at the first end and the second end. Thescrews 210, 212 extend through threaded holes formed in end walls 213 a,213 b of the brackets 203, 204. The input force compression mechanismalso includes two end pieces 214 and 216 that are disposed inside thespace defined by the brackets. The end pieces 214, 216 are positioned soas to be acted on by the ends of the screws 210 and 212, respectively.

Each of the end pieces 214, 216 has a flat surface 217 on one end thatis orthogonal to the z-direction and an angled sliding surface 218having an oblique angle with respect to the z-direction on the otherend. The end of each screw 210, 212 makes positive contact with the flatsurface 217 of the respective end piece 214, 216 to input one or morecompression forces. The screws are movable by rotating the screws in theappropriate direction, which causes the screws to move in thez-direction and exert an input compression force on the end pieces 214,216.

Although the clamp 200 has been described as having two input forcecompression mechanisms, one mechanism at each end of the clamp, a singleinput force compression mechanism can be used. In addition, even if twoinput force compression mechanisms are provided on the clamp, onemechanism can remain fixed while only one mechanism is used to apply aninput compression force.

In addition, although the use of screws and end pieces to form the inputcompression mechanisms has been described, other input compression forcemechanisms can also be used as long as they can input a compressionforce to the plurality of force converting elements.

The cardlock clamp 200 further has a plurality of force convertingelements 220-233 disposed therein. In the illustrated embodiment, theforce converting elements 220-233 are in the form of multidirectionalwedges that are identical to each other. However, it is contemplatedthat the force converting elements need not be identical to each other.Each multidirectional wedge has at least two angled sliding surfacesengaged with corresponding angled sliding surfaces of an adjunct wedgeas to convert the compression force into clamping forces in at least tworadial directions. The multidirectional wedges are illustrated as doubleended wedges having two angled sliding surfaces in the cardlock clamp200. However, multidirectional wedges having more than two angledsliding surfaces can also be used.

The double ended wedges are aligned along the z-direction between thetwo end pieces 214 and 216. The double ended wedges are engaged witheach other and are configured to convert the input compression forces inthe z-direction from the end pieces 214 and 216 into clamping forces inat least two radial directions, such as the x-direction and they-direction. Although 14 double ended wedges are illustrated, a largeror smaller number of wedges can be used. In general, the more doubleended wedges that are used, the more uniform the clamping forces aredistributed on the inner surfaces of the brackets.

FIG. 3( a) illustrates a perspective view of one of the double endedwedges 222. Since the wedges are identical, only one wedge will bedescribed. The double ended wedge 222 has a first angled sliding surface302 at one end and a second angled sliding surface 304 at the other end.Each of the angled sliding surfaces forms an oblique angle with respectto the z-direction. As illustrated in FIG. 3( b), the double ended wedge222 can be formed from a rectangular cuboid 310 by cutting away twotriangular prisms 320 and 330 and cutting away two triangular prisms 321and 331 at corners so that the remaining part 340 resembles a pair ofback to back wedges 342 and 344 (shown as the shaded surfaces in FIG. 3b) with one wedge rotated relative to the other. The wedges 342 and 344form angles α and β with respect to the z-direction, respectively. Theangles α and β are changeable. The ratio between the clamping forces inat least two radial directions, such as the x-direction and they-direction can be adjusted by varying the angles α and β.

FIG. 4( a) illustrate another embodiment of a double ended wedge. Thedouble ended wedge 440 has a first angled sliding surface 442 and asecond angled sliding surface 444 (shown as the shaded surfaces in FIG.4 a). Each of the angled sliding surfaces is oblique with respect to thex-direction, the y-direction and the z-direction and matches with anangled sliding surface of end piece 420, 430.

FIG. 4( b) illustrate 7 identical double ended wedges 440 engage witheach other and engage with the end pieces 420 and 430. Similar to thedouble ended wedge 222, the double ended wedges 440 are engaged witheach other and are configured to convert an input compression forces inthe z-direction from the end pieces 420 and 430 into clamping forces inat least two radial directions, such as the x-direction and they-direction. The ratio between the clamping forces in the at least tworadial directions can be adjusted by varying angles between the angledsliding surfaces of the double ended wedge 440 and the at least tworadial directions.

With reference to FIGS. 2( b) and 2(c), the end pieces 214 and 216 areengaged with the double ended wedges 220 and 233, respectively. Theangled sliding surface 218 of the end piece 214 matches the first angledsliding surface 302 of the double ended wedge 220, and the angledsliding surface 218 of the end piece 216 matches the second angledsliding surface 304 of the double ended wedge 233. The double-endedwedges are also arranged and oriented relative to one another so thatthey are engaged with each other through their respective angled slidingsurfaces.

For example, as shown in FIG. 2( c), the double ended wedge 223 isengaged with its adjacent double ended wedges 222 and 224 through theirrespective angled sliding surfaces. The second angled sliding surface ofthe double ended wedge 222 matches the first angled sliding surface ofthe double ended wedge 223, and the second angled sliding surface of thedouble ended wedge 223 matches the first angled sliding surface of thedouble ended wedge 224.

The configuration and ultimate arrangement of the wedges in the brackets202, 204 is such that upon a compression force input by one or both ofthe input compression force mechanisms, the column of wedges expands inall directions orthogonal to the compression force. The expansion of thewedges acts on the brackets to create the clamping forces. The wedgesremain in-line with the longitudinal axis (along the z-direction) of thecardlock clamp.

For example, upon the input compression force from the screw(s) 210 or212 through the end pieces 214 and 216, each of the double ended wedgeshas first and second angled sliding surfaces 302, 304 configured toslide with respect to adjacent matching angled sliding surfaces. Forexample, as shown in FIG. 2( c), the first angled sliding surface 302 ofthe double ended wedge 223 is configured to slide with respect to thesecond angled sliding surface 304 of the double ended wedge 222, and thesecond angled sliding surface 304 of the double ended wedge 223 isconfigured to slide with respect to the first angled sliding surface 302of the double ended wedge 224. The first angled sliding surface of thedouble ended wedge 220 is configured to slide with respect to the angledsliding surface of the end piece 214, and the second angled slidingsurface of the double ended wedge 233 is configured to slide withrespect to the angled sliding surface of the end piece 216. In thismanner, the column of double ended wedges is movable both in thex-direction and in the y-direction upon application of the inputcompression force.

The double ended wedges are supported by the L-shaped brackets 202 and204. Consequently, as shown in FIG. 5, the L-shaped brackets 202 and 204are pushed away from each other by the double ended wedges uponapplication of an input compression force, generate clamping forces bothin the x-direction and in the y-direction as illustrated by the arrowsin FIG. 5.

Upon an input compression force, the double ended wedges convert thecompression force into clamping forces in at least two radial directionsperpendicular to the compression force and expand the L-shaped bracketsin the radial directions such as the x-direction and the y-direction.Note that even if the L-shaped brackets are constrained in expanding inone or more of the at least two radial directions, the L-shaped bracketscan still expand in the remaining radial directions upon the inputcompression force. For example, the clamp 200 in FIG. 1 expands in they-direction to contact the side surfaces of the channel 120 and stopexpanding, while the clamp can still expand in the x-direction until itmeet constrains in the x-direction.

Since the double ended wedges are free to move independently and remainin-line with the longitudinal axis of the cardlock clamp, theyself-center and self-align the cardlock clamp with respect to thechannel of the card cage. For example, if a first end of a cardlockclamp (such as the cardlock clamp 200) is placed at a first end with astandard width of a channel, but a second end opposing to the first endis at a second end of the same channel wider than the first end, thewedges at the second end would tend to displace more than those at thefirst end until forces between the wedges became balanced, therebycreating a distributed loading on the cardlock clamp.

FIGS. 6( a) and (b) illustrate another embodiment of a cardlock clamp500 that incorporates the concepts described herein. The cardlock clamp500 includes a member in the form of two elongated L-shaped brackets 502and 504 similar to the L-shaped brackets 202 and 204 described above.The L-shaped brackets 502 and 504 are only partially illustrated in FIG.6 a. When assembled, the brackets 502, 504 define a space that receivesa plurality of force converting elements in the form of wave springs520, 522, 524.

An input compression force mechanism is disposed at each end of thebrackets. Similar to the clamp 200, each input compression forcemechanism of the clamp comprises a screw 510 that extends through athreaded hole in an end wall 511 of one of the brackets. Each screw hasa head 512 to facilitate actuating the screw, and the screw is engagedwith or is integral with a plate 514.

The wave springs 520, 522 and 524 are disposed inside the space definedby the brackets 502, 504 and each wave spring has ends engaged by theplate 514. By actuating one or more of the screws 510 in the appropriatedirection, an input compression force is applied to the wave springs.

FIG. 6( b) illustrates an exemplary arrangement of the wave springs 520,522 and 524 inside the space. The wave springs extend along thez-direction. The wave spring 520 is horizontal and is flanked by thewave springs 522 and 524 orthogonally. It is contemplated that the wavesprings can be interwoven. The wave spring 520 is expandable in thex-direction and the wave springs 522 and 524 are expandable in they-direction when compressed. The amount of expansion of the wave springscan be suitably controlled by the configuration and material of the wavesprings. Although three wave springs are described, any other number ofwave springs greater than one can be used. For example, two wave springsalong the z-direction, one being horizontal and the other being verticalcan be used.

Upon an input compression force from the screw 510, the wave springs520, 522 and 524 are compressed in the z-direction. The wave spring 520expands in the x-direction and makes positive contact with at least oneof the inner surfaces of the brackets. At the same time, the wavesprings 522 and 524 expand in the y-direction and each of the wavesprings 522 and 524 makes positive contact with the inner surfaces ofthe brackets. Consequently, the two L-shaped brackets 502 and 504 arepushed away from each other by the wave springs and generate clampingforces both in the x-direction and in the y-direction. When the screwforce is withdrawn, each wave spring would recover its original shape toremove the clamping forces.

FIGS. 7( a) and (b) illustrate another embodiment of a cardlock clamp600 that incorporates the concepts described herein. The cardlock clamp600 has a plurality of force converting elements in the form of springpins that are engaged with each other. Although not illustrated in FIGS.7( a)-(b), the spring pins can be disposed within a member that includesone or more input compression force mechanisms. For example, the member,including the input force compression mechanism, in this embodiment canbe similar to the L-shaped brackets and input compression forcemechanisms discussed above. Another suitable input compression forcemechanism will be discussed below with respect to FIG. 8.

FIG. 7( a) is a side view of a plurality of the spring pins engaged witheach other. Five pairs of spring pins 610 and 620, 630 and 635, 640 and645, 650 and 655, and 660 and 665 are engaged with each other in thez-direction, respectively, forming an elongated, stacked arrangement.The spring pins are identical to each other. Although five pairs ofidentical spring pins are described, any other number of spring pins canbe used to be engaged with each other. For example, FIG. 8 illustratesone pair of spring pins.

With reference to FIG. 7( b) which shows the spring pin 610 as anexample, each spring pin has an expandable sleeve section 611 with a gap613 and a tang section 612 extending from the sleeve section oppositethe gap. The sleeve section 611 has an outer surface and an innersurface which are concentric. The gap 613 is defined by two sidesurfaces normal to the outer surface and the inner surface of the sleevesection 611. The tang section 612 has two sliding surfaces matching theside surfaces of the gap 613. The tang section 612 and the gap 613 arecomplementary to each other so that the tang section can fit into thegap of an adjacent spring pin as illustrated in FIGS. 7( a) and 8. Thetang section 612 tapers in size as it extends away from the sleevesection 611. Similarly, the gap 613 tapers in size as it extends awayfrom the tang section 612.

Returning to FIG. 7( a), the tang section of one spring pin isconfigured to fit into the gap of an adjacent spring pin. For example,the spring pin 610 engages and pairs with the spring pin 620. The tangsection 612 of the spring pin 610 fits into the gap 613 of the springpin 620, while the tang section 612 of the spring pin 620 fits into thegap 613 of the spring pin 610. Upon application of a compression forceon one or both axial ends of the pin 610 or pin 620, the tang sections612 sliding in the gaps 613 cause expansion of the sleeve sections 611radially in all directions substantially perpendicular to thez-direction.

The other pairs of spring pins operate in a similar manner. Upon aninput compression force on the end of at least one of the spring pins610 or 665, each of the tang sections 612 slides into their respectivegap 613, which expands the corresponding sleeve section 611 radially.The radial expansion of the sleeve sections 611 acts on the member,generating clamping forces in all directions substantially perpendicularto the z-direction to hold the circuit card in place in the channel.

FIG. 8 shows a cardlock clamp that uses a pair of the spring pins 610and 620 engaged with each other. The tang section 612 of the spring pin620 fits into the gap 613 of the spring pin 610 and expands the sleevesection 611 radially. In addition, the tang section 612 of the springpin 610 fits into the gap 613 of the spring pin 620 and expands thesleeve section 611 radially. The input compression force mechanismincludes a screw 730 and a nut 740. The screw 730 extends through thepins 610, 620 and is fixed to a head 735 that is engaged with the end ofthe spring pin 620. The pins 610, 620 are thus clamped between the head735 and the nut 740. Rotation of the nut 740 in the appropriatedirection draws the head 735 and nut 740 closer together, whichgenerates a force driving the tang sections 612 into the gaps 613,thereby expanding the sleeve sections 611 radially. The clamp of FIG. 8can be used with or without a member.

The spring pins in FIGS. 7( a)-(b) and 8 can also be used as a clampmechanism in other applications. For example, the spring pin clampmechanism in FIG. 8 could be used as an anchor in a blind hole such asin concrete. When used as an anchor in a blind hole, the clamp mechanismin FIG. 8 can be used without a member since the screw 730, head 735 andnut 740 will hold the spring pins together. Therefore, the clampmechanism would include a plurality of force converting elements in theform of the spring pins and an input force compression mechanism. Theclamp mechanisms in FIGS. 2( a)-(c), FIGS. 6( a)-(b) and FIG. 9 may alsobe effective as anchors in a blind hole, but would likely utilize amember to retain the plurality of force converting elements in place.

FIG. 9 illustrate another embodiment of a cardlock clamp 1000 thatincorporates the concepts described herein. The cardlock clamp 1000 hasa plurality of force converting elements in the form of tubes 1010-1025that are engaged with each other. The tubes are disposed within a memberin the form of two elongated L-shaped brackets 1002 similar to theL-shaped brackets discussed above. An input compression force mechanism1006, similar to the input compression force mechanism in the cardlockclamp 500 of FIG. 6( a), is disposed at each end of the brackets.

The tubes are arranged with longitudinal axes along one of radialdirections, such as an x-direction and a y-direction. For example, thetube 1010 is arranged with its longitudinal axis along the x-directionand the tube 1025 is arranged with its longitudinal axis along they-direction. The tubes are compressible so that an input compressionforce along a z-direction from the input compression force mechanism1006 would compress the tubes in the z-direction and expand the tubes inthe x-direction or in the y-direction. Consequently, the L-shapedbrackets 1002 are pushed away from each other by the tubes and generateclamping forces both in the x-direction and in the y-direction. Althoughthe tubes are illustrated as having a cylindrical shape before applyingthe input compression force, tubes having other cross sectional shapescan be used, such as rectangle, polygon, oval or irregular shapes. Inaddition, although the tubes are illustrated as hollow, solid tubes canbe used.

The ratio between the clamping force in the x-direction and in they-direction can be controlled by varying the number of tubes facing inthe x-direction and the number of tubes facing in the y-direction.Although 16 tubes are illustrated with 4 of them facing in thex-direction and 12 of them facing in the y-direction, a larger orsmaller number of tubes can be used with an appropriate number of themfacing in the x-direction and the remaining tubes facing in they-direction.

FIGS. 10( a) and (b) illustrate another embodiment of a cardlock clampused to secure a circuit card in a channel. The cardlock clamp 800 has amovable clamp body including two L-shaped brackets 810 and 820, and amechanism 830 for applying a clamping force to the clamp body. Thecardlock clamp 800 can function similarly to the cardlock clamps 200,500, 600 described above, with the L-shaped brackets 810 and 811 similarto the brackets 202 and 204 described in the cardlock clamp 200, and themechanism 830 configured to input a compression force to a plurality offorce converting elements. Alternatively, the cardlock clamp 800 can besimilar to conventional cardlock clamps that operate based on an inputtensile force, but with a highly conductive material discussed furtherbelow.

In the cardlock clamp 800, the L-shaped brackets 810, 820 are preferablymade of a ceramic material suitable for receiving a diamond coating. Inother embodiments, the clamp body can be made of other materials as longas those materials are able to receive a diamond coating thereon. TheL-shaped brackets are identical in construction, with the bracket 810having a first surface 811 and a second surface 812 connected to thefirst surface 811, and the bracket 820 having a first surface 821 and asecond surface 822 connected to the first surface 821.

A thick diamond coating is disposed on the first and second surfaces ofthe L-shaped brackets. For example, a first layer of diamond is coatedon the first surface 811 and the second surface 812 of the L-shapedbracket 810; a second layer of diamond is coated on the first surface821 and the second surface 822 of the L-shaped bracket 820.

FIG. 10( b) is a partial cross sectional blow-up view of FIG. 10( a).The layer of diamond 860 is coated on the surface of the bracket 820.The diamond layer has a thickness of, for example, about 0.03 inches.The layer of diamond 860 has a substantially flat surface finish and ismade of, for example, diamond by physical or chemical deposition. Inother embodiments, the layer of diamond 860 can be made of other highlythermally conductive materials such as diamond-like carbon, synthesizedcarbon, carbon nano-tube, copper, aluminum or their compounds. Thematerial of the diamond or other highly thermally conductive materialcoatings has higher thermal conductivity than the material of the clampbody.

Returning to FIG. 10( a), since the material of the diamond coating hashigher thermal conductivity than the material of the clamp body, thediamond coating defines two heat transfer paths: one from the firstsurface 811 to the second surface 812 of the L-shaped bracket 810, theother from the first surface 821 to the second surface 822 of theL-shaped bracket 820. For example, when the cardlock clamp 800 isinstalled, the diamond coating 860 on the first surface 821 of theL-shaped bracket 820 makes positive contact with the circuit card, andthe diamond coating 860 on the second surface 822 makes positive contactwith a heat sink, such as the bottom or side surface of the channel 120in the card cage 100; at the same time, a diamond coating on the firstsurface 811 of the L-shaped bracket 810 makes positive contact with thecircuit card, and the diamond coating on the second surface 812 makespositive contact with the heat sink, such as the side or bottom surfaceof the channel 120 in the card cage 100. Heat is transferred from thecircuit card along the two heat transfer paths to the heat sink insteadof propagating through the clamp body. However, it is contemplated thatthe clamp body itself can be made of highly thermally conductivematerials such as diamond, diamond-like carbon, synthesized carbon,carbon nano-tube, copper, aluminum and their compounds so that heat canbe transferred from the circuit card through the clamp body.

FIG. 11 illustrate another embodiment of a cardlock clamp 900. Thecardlock clamp 900 has a clamp body including a first movable bracket910. The bracket 910 is, for example, an L-shaped bracket which ishollow and has inner and outer surfaces which define a closed cavity.The bracket 910 is made of, for example, materials which can conductheat. The cardlock clamp 900 also has a mechanism 930 for applying aclamping force to the first bracket 910. The cardlock clamp also has asecond movable bracket 920 similar to the first movable bracket 910.

At least one of the brackets 910, 920 is configured as a heat pipe. Forexample, the first movable bracket 910 can be configured as a heat pipe.The heat pipe has a vaporization side 911, a condensing side 912 spacedfrom the vaporization side 911, and a two-phase heat transfer fluid 913is disposed within the closed cavity of the bracket 910.

When the cardlock clamp 900 is installed, the vaporization side 911engages the circuit card and the condensing side 912 engages a heatsink. Heat is transferred from the circuit card along the heat pipe tothe heat sink through the two-phase heat transfer fluid 913.

Although the bracket 910 is described as being configured as a heatpipe, in other embodiments, at least one heat pipe can be embeddedinside the bracket 910. Alternatively, the at least one heat pipe can beattached to the outer surfaces of a solid bracket. The at least one heatpipe may follow a serpentine path to allow sonic velocities for thethermal transfer from the condensation portion to the vaporizationportion.

The examples disclosed in this application are to be considered in allrespects as illustrative and not limitative. The scope of the inventionis indicated by the appended claims rather than by the foregoingdescription; and all changes which come within the meaning and range ofequivalency of the claims are intended to be embraced therein.

1. A spring pin, comprising: a radially expandable sleeve section havinga first end and a second end; a gap formed in the expandable sleevesection from the first end to the second end, the gap is defined by twospaced side surfaces, and the gap tapers in size such that a distancebetween the side surfaces increases as the gap extends from the firstend; and a tang section extending from the first end of the expandablesleeve section at a location opposite the gap, the tang section isdefined by two sliding surfaces, and the tang section tapers in sizesuch that a distance between the sliding surfaces decreases as the tangsection extends away from the expandable sleeve section.
 2. The springpin of claim 1, wherein the gap and the tang section are complementaryin shape to one another.
 3. The spring pin of claim 1, wherein the gaptapers in size the entire distance from the first end to the second end,and the tang section tapers in size along the entire length of the tangsection.
 4. The spring pin of claim 1, wherein the expandable sleevesection is ring-shaped with a central opening from the first end to thesecond end, the central opening has a longitudinal axis perpendicular toan expansion direction of the expandable sleeve section and parallel tothe tang section.
 5. A clamp mechanism, comprising: first and secondspring pins, each of the spring pins including: a radially expandablesleeve section having a first end and a second end; a gap formed in theexpandable sleeve section from the first end to the second end, the gapis defined by two spaced side surfaces, and the gap tapers in size suchthat a distance between the side surfaces increases as the gap extendsfrom the first end; and a tang section extending from the first end ofthe expandable sleeve section at a location opposite the gap, the tangsection is defined by two sliding surfaces, and the tang section tapersin size such that a distance between the sliding surfaces decreases asthe tang section extends away from the expandable sleeve section thefirst and second spring pins are arranged such that the tang section ofthe first spring pin is within the gap of the second spring pin, and thetang section of the second spring pin is within the gap of the firstspring pin; and an input compression force mechanism engaged with thefirst and second spring pins and that is configured to input acompression force in a z-direction perpendicular to the radial expansiondirection of the first and second spring pins, wherein application of acompression force by the input compression force mechanism causeexpansion of the expandable sleeve sections of the first and secondspring pins radially in all directions substantially perpendicular tothe z-direction.
 6. The clamp mechanism of claim 5, wherein for thefirst and second spring pins, the gap and the tang section arecomplementary in shape to one another.
 7. The clamp mechanism of claim5, wherein for each of the first and second spring pins, the gap tapersin size the entire distance from the first end to the second end and thetang section tapers in size along the entire length of the tang section.8. The clamp mechanism of claim 5, wherein for each of the first andsecond spring pins, the expandable sleeve section is ring-shaped with acentral opening from the first end to the second end, the centralopening has a longitudinal axis perpendicular to an expansion directionof the expandable sleeve section and parallel to the z-direction, andthe central openings of the first and second springs pins are alignedwith each other.
 9. The clamp mechanism of claim 5, wherein the inputforce compression mechanism is configured to engage the second end ofone or both of the first and second spring pins.
 10. The clamp mechanismof claim 8, wherein the input force compression mechanism comprises ascrew that extends through the aligned central openings of the first andsecond spring pins, a head at one end of the screw, and a nut thatthreads onto the screw, and the first and second spring pins aredisposed between the head and the nut.
 11. The clamp mechanism of claim5, further comprising a member that defines a cavity in which the springpins are disposed.
 12. The clamp mechanism of claim 11, wherein themember comprises a plurality of brackets that are moveable relative toeach other and that define the cavity.